Hardening oven saga

[brino]

Hey Ted,

Check out this propane burner:
http://www.backyardmetalcasting.com/oliverburner1.html

I have made several of those that I use for melting aluminum, forging steel, killing weeds, boiler for steam bending, etc.

-brino

(In fact his whole site has lots of info: http://www.backyardmetalcasting.com/ )

 

[Ferrous Turner]

Thanks brino! That's the kind of info I need. I may get an adjustable regulator since I don't know the pressure of this particular one. I also have the flame burning up in the pipe which doesn't seem good. That may be because the pressure is too low, or the pipe is too big or who knows...
I need to do some shopping.

 

[Ferrous Turner]

I was experimenting with a blower today. The blower is much more than I need, but I had it so I used it. I put a valve in to adjust the airflow.

It works pretty good, but I'm having a hard time keeping the flame going. It has a tendency to sputter and then go out.
This picture makes it look like it's working better than it is (long exposure).

This is the nozzle I used, but it's not what I need. I'm going to try one of those flat flared type.

I also ordered an adjustable regulator, which may help. So many variables...

 

[dlane]

I kinda made a oliverupwind burner worked good 035 mig tip in the pipe, the forge was a insulated air tank here’s the burner and tank,


You may want to put a hole out the back too , for longer objects

 

[Ferrous Turner]

Nice forge!
I've been thinking about the physics involved in making a good burner. It's very similar to an internal combustion engine. You want to get the proper fuel / air mixture, and the more fuel and air you can get into the combustion chamber the better.
For a burner, the difference is that the flame has to be self sustaining. In my current set-up I have a problem of too much air velocity, which the combustion rate of the flame can't support. This is due to the small pipe diameter. By increasing the diameter of the feed pipe the velocity will decrease, thereby allowing the flame to maintain itself under a higher volume of mix. Oliver gets this in the flare at the end of his pipe (which is a nice design).
I'm also a little suspicious of my regulator. I'm getting flame sputter and I'm wondering if I'm getting a consistent flow of gas. It could also very well be the aerodynamics of my pipe arrangement. Having the air mixing with the gas in that 90 degree coupling is far lees than optimal. It could be causing an oscillation which would also account for the sputtering.
I'm still determined to get the blower design working. When I get the new regulator I'm going to change the whole design.

 

[Ferrous Turner]

I did some more research and found out some interesting stuff. There has to be something in the pipes to mix up the gas and air more. I'm going to try a couple of things and let you know how they turned out.

 

[rgray]

Here is my adventure. Inspired by ray c. Built in 14 and still going. I have started on a smaller version but not finished it.
https://www.hobby-machinist.com/threads/oven-heating-element-mounting-tmi.22103/#post-266704

 

[rgray]

I also have a "store bought" forge. The nozzle does not point right at the crucible. It is at an angle to get a swirl and heat all sides (it's round). But just getting some angle to get some swirl will help even out the heat.
If your gonna melt metal and cast it you will want to stand that oven on end and put a hole in the door. And move the nozzle closer to the bottom.
That may not be you intention at all but it is lots of fun. Takes about 125 pop cans to fill a #6 crucible

 

[Ferrous Turner]

While waiting for parts to arrive, I've been looking at some of the different burners people use for their forges. I am particularly impressed by the ribbon burners. The guys say that they are more efficient than the single burners, and I like the wider area of heat they deliver. This is your typical forge ribbon burner:

It has an upper steel plenum which sits outside the forge. The bottom is cast out of refractory cement, typically using crayons to form the holes (which are then easily removed after setting).
I assume they are built this way to keep the plenum from getting too hot and exploding (makes sense to me anyway). However, I hear some guys are having problems with their castings cracking and deteriorating. This may also be from guys who have their forge running all day.
Anyway, these burners seem like a better alternative to me. I'm going to build one this weekend and test it out.

 

[francist]

Hmmm, "lost crayon casting", I like it.

-frank